The broad objective of this research is to provide information regarding the role of arousal mechanisms in conditioned steady potential responses. Using the rat as an experimental model, cortical steady potential (SP) responses will be elicited by a conditioned stimulus reinforced wih food or foot-shock. Amphetamine and pentobarbital will be used to alter the state of arousal. Since SP responses (i.e., the CNV) may prove to be useful parameters of brain function in humans, it is essential to gain a basic understanding of the processes involved in the generation of these potentials and how they are influenced by drugs. The information derived from this project can aid in that understanding.